I don't know why you think none were mentioned - to name one, they link a GitHub issue created against the systemd repository by a Googler complaining that systemd is inappropriately using Google's NTP servers, which at the time were not a public service, and kindly asking for systemd to stop using them.
This request was refused and the issue was closed and locked.
Behaviour like this from the systemd maintainers can only appear bizarre, childish, and unreasonable to any unprejudiced observer, putting their character and integrity into question and casting doubt on whether they should be trusted with the maintenance of software so integral to at least a reasonably large minority of modern Linux systems.
Unfortunately this makes modern Linux not reliable.
https://github.com/systemd/systemd/pull/554
What's your suggested alternative?
Using pool.ntp.org requires a vendor zone. systemd does not consider itself a vendor, it's the distros shipping systemd which are the vendor and should register and use their own vendor zone.
I don't care about systemd either way, but your own false representation of facts makes your last paragraph apply to your "argument".
That if they do not wish to ship a safe default, they do not ship a default at all.